The invention generally relates to apparatus and methods for processing multiple workpieces with plasma.
Disk drives are widely used in various applications, particularly in the computer industry. In particular, disk drives are used to store large amounts of data/information in magnetizable form on a platter. The platter is supported on a motor-driven spindle and spun by the hard disk drive. Data/information is written to magnetic media on the platter using one or more write heads and is read from the magnetic media using one or more read heads.
Each write head applies a magnetic field that selectively magnetizes regions of a thin film of magnetizable material in the magnetic media deposited on the platter. Typically, the platters are made from a non-magnetic material, such as an aluminum alloy or glass, and the magnetic media is deposited on both sides of the platter. After the magnetic field produced by the write head is removed, the magnetic media in the various regions of the platter retains the magnetization. The direction of the magnetization matches the direction of the applied magnetic field, which permits non-volatile storage of the digitally written data/information in a binary format. The pattern of magnetization embedded in the magnetic media on the platter can subsequently produce an electrical response in the read head, which permits the stored data/information to be read.
Patterned magnetic recording media is being considered as a promising approach for increasing the storage density of a disk drive platter. Discrete track recording (DTR) and bit patterned media (BPM) are two specific patterning techniques capable of boosting capacity beyond current levels. A relatively new process that is amenable for use in patterning magnetic recording media is imprint lithography, which is not limited by the constraints of photolithography.
Imprint lithography relies on a master template to imprint a pattern in a liquid resist dispensed onto the magnetic recording media and then photocures the patterned liquid resist with radiation transferred through the master template. After the template is removed, the photocured pattern of resist forms an etch mask that is a replica of the pattern on the master template. The etch mask includes thick regions and relatively thin regions modulated as a mirror image of the pattern of raised and recessed features on the master template. Resist in the thin regions is removed using an anisotropic dry etching process, such as reactive ion etching. Because of the thickness difference, resist remains in the relatively thick regions of the etch mask after the thin regions are removed. Dry etching is continued with a different etch recipe to transfer the pattern from the etch mask to the underlying layer.
Efficient, cost-effective methods and apparatus are desired for removing the cured resist material from the thinned regions of the patterned mask.